JP spot welder

[markz]

So you are saying its better to have a web like structure, rather then 1 or 2 paths for current.
In a square 4x4 block of batteries, P first then series.

View attachment 2
So three of these, 2 on one side (one connecting rows 1 and 2 then 3 and 4), one on the other (connecting rows 2 and 3).
Then input and output rows. Input opposite side of row 1, and opposite side of row 4.
Instead of having one interconnect in the middle, be better to have 4.

Basically saying, for each battery can, you want the current to travel the same distance for each can.

These 2 diagrams do not show current equalization. #2 is close, but what I am saying is have 2 more paths that cross, in the middle.
View attachment 1

This is ideal, however making input and output lengths (4 on each, exactly the same length of wire or metal strip)

 

[fechter]

I think you got it.

There's a better picture from Doctorbass here:
https://endless-sphere.com/forums/viewtopic.php?f=14&t=61604#p920396

The series connections really have to take most of the current so if you have many of them, like one for each cell in a parallel group, they can be thinner than if you lump the entire current into a single conductor. Ideally, the parallel connections take nearly zero current. As Doctorbass points out, there are really two issues, one is the current balance and the other is having enough copper so nothing gets hot. The goal is to satisfy both issues.

There are times when you need to lump all the current into a single conductor for each parallel group. Not ideal, but may make construction much easier. In that situation, my diagram 1 would be a good approach. In this situation the parallel connection must take all the series current as well, so must be beefed up to handle the full discharge current.

This is all going a bit OT, but certainly worthy of discussion. Perhaps a new topic.

 

[Offroader]

OK, I went back to the drawing board once gain to update my pack.

Sorry if this is considered off topic about building this pack. Please recommend if I should post in another thread.

Here is an updated version of my pack. I will use 6 series connections soldered between every two cells so that every cell discharges the same distance to the series connections.
I also will use the same length 16 AWG for all 6 connections to each group in the series. Every two cells will all have the same length wire as the other cells in the parallel group.

Copper plating will be .2x8mm thickness.

16AWG has an amp rating of 22 amps. 22x6 = 132 amps. Or each 16AWG wire will connect two cells with a maximum amp draw of 10 amps.

I see no need to use copper plates connecting all cells as a web, I will only put a small plate to connect all 12 cells together where needed for balancing purposes only.

How does this look now? Is it perfectly equal distribution?
Do I need to add copper plates to web all the cells together? Or is how I have it OK in the picture.

Thanks.

 

[tomjasz]

Nobuo. aka Damian Rene

https://vimeo.com/user8096026

https://www.youtube.com/user/DamianBSS

 

[fechter]

OK, I went back to the drawing board once gain to update my pack.

Sorry if this is considered off topic about building this pack. Please recommend if I should post in another thread.

That looks great (as far as I can tell). A little hard to follow the picture. The only thing is on the main pack + and - connections you probably want a heavy wire across the cells to spread out the current. Alternately you could use multiple small wires like your intercell connections and bundle them together and splice to the main output wires. Sort of like an exhaust header.

 

[Offroader]

Yes that is a good idea to use 6 wires to connect to the main battery leads.

Using the copper wires was a great idea instead of nickel plates. I honestly wonder how I could have used plates to connect that pack and pass 120 amps through them.

Because of my odd shape pack to fit my battery compartment, I don't have the luxury of building a rectangular pack that would allow easier cell placement for nickel plates. The copper wires really helps to easily pass the current through and the other advantage is it is cheaper and probably will be less weight as copper is much better than nickel to pass current.

 

[Cowardlyduck]

Looking better (although messy) Offroader.

It might look like a mess, but that really won't matter once it's all sealed up and working well.
I recently re-built an old 22650 pack where some of the connections follow a similar approach:

This pack is only really low draw, so it really didn't need multiple series connections, but I don't care...I like to do things well when possible and it was really good practice (having never done it before) for when I build my future 18650 packs.

Something I would add from my experience though...be really careful when soldering on the positive end of the cells. I had a few cases where solder dripped over onto the cell can creating a short...had to react pretty quickly to prevent catastrophe. :lol:

Cheers

 

[Kepler]

Yes that is a good idea to use 6 wires to connect to the main battery leads.

Using the copper wires was a great idea instead of nickel plates. I honestly wonder how I could have used plates to connect that pack and pass 120 amps through them.

Because of my odd shape pack to fit my battery compartment, I don't have the luxury of building a rectangular pack that would allow easier cell placement for nickel plates. The copper wires really helps to easily pass the current through and the other advantage is it is cheaper and probably will be less weight as copper is much better than nickel to pass current.

Have you considered building 2 x 20S6P or 2 10S12P brick packs with 20mm plastic spacers and stacking them on top of each other. Pack would be much neater and easer to build. Width would be 120mm so you wouldn't be wasting all the side space. If you went 20S6P by 2, you could run with just one pack for shorter distances and add the second to double your range. Just a thought.

 

[Offroader]

I am building this pack for a Qulbix Q76R which has a 76mm wide frame.

 

[Kepler]

I see. Continue as you were.

 

[riba2233]

I don't have problem with off topic but I think this area deserves it's own thread, and this would be ok start

 

[Cowardlyduck]

I don't have problem with off topic but I think this area deserves it's own thread, and this would be ok start

Agree. Maybe it could be added to this thread?
https://endless-sphere.com/forums/viewtopic.php?f=14&t=68005

Cheers

 

[riba2233]

Yeah, last few posts could be merged to that topic :wink:

 

[mistercrash]

Can the JP Welder weld 1 mm thick Zinc sheets to 18650 cells? I know nothing about metals and welding but seeing that Zinc has a melting point of around 450 degrees Celsius compared to around 1450 degrees for Nickel. I thought maybe it could be possible?

 

[riba2233]

Can the JP Welder weld 1 mm thick Zinc sheets to 18650 cells? I know nothing about metals and welding but seeing that Zinc has a melting point of around 450 degrees Celsius compared to around 1450 degrees for Nickel. I thought maybe it could be possible?

It's hard to say, I'd have to try, but I am tempted! I will try getting some and then try. I did that with aluminum but it was flop It just sucks too much oxygen and becomes too soft. It has melting temp of around 660°C.

 

[joostj]

Just received my new battery electrodes and cables. Extremely impressed. Going to be so much easier using these now.
Before I was worried about my a123 20ah tabs because of all the movement required. Just looking at the picture showing
them in a circle shows how playable they are.

Thanks Riba great improvement.

Where can I get a set of these leads?

 

[Offroader]

I'm trying to decide on the thickness and width of the nickel plates. Each plate will connect two cells that will have a soldered wire soldered between both cells for the series connection. The max draw will be 10 amps per cell.

I have some questions that I was hoping you guys can help me out with.

1) If I use .2mm nickel, what is the optimal width to make each connection? Would it be best to use .2mmx7mm or better to use something like .2mm x 10mm or .2mm x 15mm? I can cut my own width so I am flexible on the width. Will wider plates even make a difference when the positive cell tab is only 7mm in width?

2) Should I consider using .3mm nickel? The width may have to be limited to 8mm width.

3) is using .3mm nickel too thick and not worth using because of problems? Basing it on this post here where he doesn't recommend .3mm and it makes sense to me.
https://endless-sphere.com/forums/viewtopic.php?p=1023075#p1023075

4) Should I consider doubling up on the nickel plate? Problem with this is I don't see how I can weld the center of the plates between both cells, or where the solder will be without welding into the battery.

5) Is it possible that because of the very short distance the current travels on the nickel plates until it hits the copper wire it is negligible what size I use?

Thanks, below is a drawing showing how I plan on connecting each two cells and the 10 amp current direction into the wire.

 

[ohzee]

Just received my new battery electrodes and cables. Extremely impressed. Going to be so much easier using these now.
Before I was worried about my a123 20ah tabs because of all the movement required. Just looking at the picture showing
them in a circle shows how playable they are.

Thanks Riba great improvement.

Where can I get a set of these leads?

Riba is the man. Just send him a PM and let him know what you need.

 

[cwah]

Hello,

I bought this power supply:
http://vod.ebay.co.uk/vod/FetchOrderDetails?ul_ref=http%253A%252F%252Frover.ebay.com%252Frover%252F0%252Fe11400.m44.l1503%252F7%253Feuid%253Dd866f0805acf4dfba43ac50e4cb9871d%2526loc%253Dhttp%25253A%25252F%25252Fpayments.ebay.co.uk%25252Fws%25252FeBayISAPI.dll%25253FViewPaymentStatus%252526transId%25253D513014401027%252526itemId%25253D401023166781%252526qu%25253D1%2526srcrot%253De11400.m44.l1503%2526rvr_id%253D0&qu=1&itemid=401023166781&transid=513014401027&viewpaymentstatus=

Would that work with the kit?

 

[tomjasz]

futile

 

[riba2233]

Where can I get a set of these leads?

I sell them, please check first post for details!

I'm trying to decide on the thickness and width of the nickel plates. Each plate will connect two cells that will have a soldered wire soldered between both cells for the series connection. The max draw will be 10 amps per cell.

5) Is it possible that because of the very short distance the current travels on the nickel plates until it hits the copper wire it is negligible what size I use?

Thanks, below is a drawing showing how I plan on connecting each two cells and the 10 amp current direction into the wire.

It's negligible, you can use 0.1 mm thick 8 mm wide nickel which is very common and cheap.

Hello,

I bought this power supply:

Would that work with the kit?

Link doesn't work, post a new one. But if you meant power supply for using instead of battery for welding answer is most probably no. If you meant only for charging welding battery or powering welder logic, then it could be ok, I just need to see the link

 

[cwah]

Hello Riba,

Here is the right link
http://www.ebay.co.uk/itm/401023166781

I wonder if amp and connector are ok?

 

[riba2233]

Well is is fine, but I've never heard of this standard:

"3 mm x 5.2 mm plug"

I don't know if it's a typo, because it looks good on pictures, but if you want to be sure, chose one that says 5.5/2.1 mm plug center positive.

 

[cwah]

Ok thanks. I bought it anyway so waiting for it to arrive and hope that it's going to be the right size

 

[Offroader]

I'm trying to decide on the thickness and width of the nickel plates. Each plate will connect two cells that will have a soldered wire soldered between both cells for the series connection. The max draw will be 10 amps per cell.

I have some questions that I was hoping you guys can help me out with.

1) If I use .2mm nickel, what is the optimal width to make each connection? Would it be best to use .2mmx7mm or better to use something like .2mm x 10mm or .2mm x 15mm? I can cut my own width so I am flexible on the width. Will wider plates even make a difference when the positive cell tab is only 7mm in width?

2) Should I consider using .3mm nickel? The width may have to be limited to 8mm width.

3) is using .3mm nickel too thick and not worth using because of problems? Basing it on this post here where he doesn't recommend .3mm and it makes sense to me.
https://endless-sphere.com/forums/viewtopic.php?p=1023075#p1023075

4) Should I consider doubling up on the nickel plate? Problem with this is I don't see how I can weld the center of the plates between both cells, or where the solder will be without welding into the battery.

5) Is it possible that because of the very short distance the current travels on the nickel plates until it hits the copper wire it is negligible what size I use?

Thanks, below is a drawing showing how I plan on connecting each two cells and the 10 amp current direction into the wire.

Tried to do some research into this and may have an answer here. Please correct me if anything seems wrong with my logic.

The 16 AWG copper wire can handle 22 amps based on this chart. This will handle the 20 continuous amps coming from the two cells. http://www.powerstream.com/Wire_Size.htm

Next I need to calculate the cross sectional area of the nickel plates to handle 10 amps, because each nickel tab is only carrying 10 amps max before entering the copper wire.

Because nickel has 4 times more resistance than copper I need a cross sectional area of nickel 4 times that of copper.

A 20 AWG copper wire can handle 11 amps.

A 20 AWG copper wire has a cross sectional area of .5176 mm². http://www.rapidtables.com/calc/wire/wire-gauge-chart.htm

In order to match that with nickel I would need about 2mm² of nickel.

This would require a .2x10mm nickel plate. = (.2) (10) = 2mm² of nickel.

Or I could use a .3mmx8mm strip which would be better at a 2.4mm².